Establishment of Reference Ranges for Left Heart Echocardiography‐Related Parameters in Seven Common Small Dog Breeds in Taiwan and Their Relationships with Body Weight, Age, and Sex

ABSTRACT Myxomatous mitral valve disease (MMVD) is a common heart disease in dogs, especially in small‐ and medium‐sized breeds. Echocardiography is the most accurate diagnostic method for MMVD. The breed has a strong influence on echocardiographic parameters. Only a few small breeds have reported reference ranges, which do not meet the needs of all small dogs. Therefore, in this retrospective study, seven common small dog breeds ( n = 100, body weight [BW] < 10 kg) in Taiwan were selected, and reference ranges for echocardiographic parameters were established for healthy small dogs. In addition, the associations between left heart echocardiographic parameters and animal characteristics were explored, including breed, BW, age, and sex. Animals who met the selection criteria underwent a complete echocardiographic examination. The reference intervals of these parameters for all dogs were presented as means ± SD and 95% CI. The relationships between each echocardiographic parameter and animal characteristics were examined using linear regression models fitted with generalized estimating equations. The results showed that the majority of small dog echocardiography parameters (IVSD, LVIDD, LVWD, IVSS, LVIDS, LVWS, EDV, ESV, SV, CO, FS%, EF%, E wave, E/A, and Ea) have a significant correlation with BW. Some parameters (IVSS, LVIDS, LVWS, ESV, EF%, FS%, A wave, E/A, Ea, and E/Ea) have a significant correlation with age. Different degrees of effects on the parameters were observed among breeds. This study provides preliminary reference ranges for echocardiography in common small dog breeds in Taiwan.